Improve [relativize] for Windows.

dart/lib/compiler/implementation/dart2js.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library('dart2js');
 
 #import('dart:io');
 #import('dart:uri');
 #import('dart:utf');
 
@@ skipping 47 matching lines @@
       if (match[i + 1] !== null) {
         handlers[i].handle(argument);
         continue OUTER;
       }
     }
     throw 'Internal error: "$argument" did not match';
   }
 }
 
 void compile(List<String> argv) {
+  bool isWindows = (Platform.operatingSystem == 'windows');
   Uri cwd = getCurrentDirectory();
   bool throwOnError = false;
   bool showWarnings = true;
   bool verbose = false;
   Uri libraryRoot = cwd;
   Uri out = cwd.resolve('out.js');
   Uri sourceMapOut = cwd.resolve('out.js.map');
   Uri packageRoot = null;
   List<String> options = new List<String>();
   bool explicitOut = false;
@@ skipping 80 matching lines @@
   int dartBytesRead = 0;
 
   Future<String> provider(Uri uri) {
     if (uri.scheme != 'file') {
       throw new IllegalArgumentException(uri);
     }
     String source;
     try {
       source = readAll(uriPathToNative(uri.path));
     } on FileIOException catch (ex) {
-      throw 'Error: Cannot read "${relativize(cwd, uri)}" (${ex.osError}).';
+      throw 'Error: Cannot read "${relativize(cwd, uri, isWindows)}" '
+            '(${ex.osError}).';
     }
     dartBytesRead += source.length;
     sourceFiles[uri.toString()] =
-      new SourceFile(relativize(cwd, uri), source);
+      new SourceFile(relativize(cwd, uri, isWindows), source);
     return new Future.immediate(source);
   }
 
   void info(var message, [api.Diagnostic kind = api.Diagnostic.VERBOSE_INFO]) {
     if (!verbose && kind === api.Diagnostic.VERBOSE_INFO) return;
     if (enableColors) {
       print('${colors.green("info:")} $message');
     } else {
       print('info: $message');
     }
@@ skipping 61 matching lines @@
   // TODO(ahe): We expect the future to be complete and call value
   // directly. In effect, we don't support truly asynchronous API.
   String code = api.compile(uri, libraryRoot, packageRoot, provider, handler,
                             options).value;
   if (code === null) {
     fail('Error: Compilation failed.');
   }
   writeString(out, code);
   int jsBytesWritten = code.length;
   info('compiled $dartBytesRead bytes Dart -> $jsBytesWritten bytes JS '
-       'in ${relativize(cwd, out)}');
+       'in ${relativize(cwd, out, isWindows)}');
   if (!explicitOut) {
     String input = uriPathToNative(arguments[0]);
-    String output = relativize(cwd, out);
+    String output = relativize(cwd, out, isWindows);
     print('Dart file $input compiled to JavaScript: $output');
   }
 }
 
 class AbortLeg {
   final message;
   AbortLeg(this.message);
   toString() => 'Aborted due to --throw-on-error: $message';
 }
 
@@ skipping 115 matching lines @@
     } catch (ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }